1. Field of the Invention
This invention relates to an analyzing apparatus to be used for performing biochemical analyses or the like.
2. Description of the Prior Art
A conventional analyzing apparatus used for performing biochemical analyses generally comprises a reagent unit for storing one or more kinds of reagents, a sample storage unit for storing samples and a reaction unit for causing a reaction between the samples and reagents. These units are normally contained in a housing provided with a cover which can be easily opened and closed. It is necessary to maintain the reagents at low temperatures in the housing. For this purpose, a Peltier element is used to configure each cooling device, for example. It is also necessary to provide a power supply/control unit for controllably turning a tray which is provided for turning the reagent unit, the sample storage unit and the reaction unit.
In the analyzing apparatus thus constructed, the cooling effect produced by cooling devices for cooling the reagent unit is impeded by heat generated by the cooling devices themselves and the power supply/control unit. An approach commonly taken in the conventional analyzing apparatus to cope with this heat problem is to remove exhaust heat to the exterior of the housing by use of an exhaust device.
On the other hand, the analyzing apparatus is provided with a cover holding mechanism which enables free open/close actions with a capability to stably hold the swingable cover at any desired position, such as the open position, the closed position, or any position halfway between the open and closed positions. This kind of cover holding mechanism is made of a gas damper mechanism, a spring-cam-hinge mechanism employing a cam mechanism and a spring, or a friction-hinge mechanism using frictional resistance, for example.
Provided with a hinge attached to a supporting edge of the swingable cover, the gas damper mechanism holds the cover at a desired position between its open and closed positions with reaction force. The gas damper mechanism is a cover holding mechanism which also produces an auxiliary force to facilitate cover-opening action, prevents the falling of the cover during its closing motion, and smoothens opening and closing motions of the cover due to sliding friction produced by a gas damper.
The spring-cam-hinge mechanism employing a spring-loaded cam mechanism is disclosed in Japanese Unexamined Patent Publication No. 10-78027, for example, in which the cover is held in a desired position by a combination of the spring and the cam mechanism. The spring produces an auxiliary force to facilitate cover-opening action and prevents the falling of the cover during its closing motion.
The friction-hinge mechanism employing a friction hinge, of which example is disclosed in Japanese Unexamined Patent Publication No. 2000-27846, holds the cover at a desired position between its open and closed positions by the frictional resistance and prevents the falling of the cover during its closing motion.
The aforementioned conventional analyzing apparatus has been associated with a problem that it is difficult to efficiently remove exhaust heat to the exterior of the housing because various units are enclosed in the single housing.
As the individual units are together contained in the housing, heat generated by the cooling devices and the power supply/control unit tends to collect around the reagent unit and such waste heat must be removed from inside the entire housing by means of the exhaust device, resulting in a poor heat exhaust efficiency. Although it would be possible to provide a heat exhausting device, such as a heat pipe, to allow for efficient heat exhaust operation, such a provision is generally expensive and makes the construction of the analyzing apparatus too complex.
The gas damper mechanism requires two kinds of sub-mechanisms, that is, the gas damper and the hinge. The gas damper requires a relatively broad dedicated space to ensure a large stroke of motion. The gas damper is also expensive and should be periodically replaced as its reaction force considerably decreases due to aging. Another problem of the gas damper mechanism is that high-pressure gases contained in the gas damper eventually become an industrial waste product.
The spring-cam-hinge mechanism employing the spring-loaded cam mechanism has a safety-related problem, because the cover would suddenly open when the direction of force exerted by a cam changes.
The friction-hinge mechanism necessitates a large force to be exerted when opening the cover to act against the frictional resistance and the weight of the cover. In addition, when an operator closes the cover, the friction-hinge mechanism does not return a feeling the cover has been fully closed. Therefore, it might be necessary to additionally provide a lock mechanism to produce a tangible response.